/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.db.mpp.execution.operator.schema;

import org.apache.iotdb.common.rpc.thrift.TSchemaNode;
import org.apache.iotdb.commons.exception.MetadataException;
import org.apache.iotdb.commons.path.PartialPath;
import org.apache.iotdb.db.metadata.mnode.MNodeType;
import org.apache.iotdb.db.mpp.common.header.ColumnHeader;
import org.apache.iotdb.db.mpp.common.header.ColumnHeaderConstant;
import org.apache.iotdb.db.mpp.execution.driver.SchemaDriverContext;
import org.apache.iotdb.db.mpp.execution.operator.OperatorContext;
import org.apache.iotdb.db.mpp.execution.operator.source.SourceOperator;
import org.apache.iotdb.db.mpp.plan.planner.plan.node.PlanNodeId;
import org.apache.iotdb.tsfile.file.metadata.enums.TSDataType;
import org.apache.iotdb.tsfile.read.common.block.TsBlock;
import org.apache.iotdb.tsfile.read.common.block.TsBlockBuilder;
import org.apache.iotdb.tsfile.utils.Binary;

import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

import static org.apache.iotdb.tsfile.read.common.block.TsBlockBuilderStatus.DEFAULT_MAX_TSBLOCK_SIZE_IN_BYTES;

public class NodePathsSchemaScanOperator implements SourceOperator {
    private final PlanNodeId sourceId;

    private final OperatorContext operatorContext;

    private final PartialPath partialPath;

    private final int level;

    private boolean isFinished;

    private final List<TSDataType> outputDataTypes;

    public NodePathsSchemaScanOperator(
            PlanNodeId sourceId, OperatorContext operatorContext, PartialPath partialPath, int level) {
        this.sourceId = sourceId;
        this.operatorContext = operatorContext;
        this.partialPath = partialPath;
        this.level = level;
        this.outputDataTypes =
                ColumnHeaderConstant.showChildPathsColumnHeaders.stream()
                        .map(ColumnHeader::getColumnType)
                        .collect(Collectors.toList());
    }

    @Override
    public OperatorContext getOperatorContext() {
        return operatorContext;
    }

    @Override
    public TsBlock next() {
        isFinished = true;
        TsBlockBuilder tsBlockBuilder = new TsBlockBuilder(outputDataTypes);
        try {
            if (-1 == level) {
                // show child paths and show child nodes
                Set<TSchemaNode> nodePaths =
                        ((SchemaDriverContext) operatorContext.getInstanceContext().getDriverContext())
                                .getSchemaRegion()
                                .getChildNodePathInNextLevel(partialPath);
                nodePaths.forEach(
                        node -> {
                            tsBlockBuilder.getTimeColumnBuilder().writeLong(0L);
                            tsBlockBuilder.getColumnBuilder(0).writeBinary(new Binary(node.getNodeName()));
                            tsBlockBuilder
                                    .getColumnBuilder(1)
                                    .writeBinary(new Binary(String.valueOf(node.getNodeType())));
                            tsBlockBuilder.declarePosition();
                        });
            } else {
                // show nodes with level
                Set<String> childNodes;
                childNodes =
                        ((SchemaDriverContext) operatorContext.getInstanceContext().getDriverContext())
                                .getSchemaRegion().getNodesListInGivenLevel(partialPath, level, false).stream()
                                .map(PartialPath::getFullPath)
                                .collect(Collectors.toSet());

                childNodes.forEach(
                        (path) -> {
                            tsBlockBuilder.getTimeColumnBuilder().writeLong(0L);
                            tsBlockBuilder.getColumnBuilder(0).writeBinary(new Binary(path));
                            tsBlockBuilder
                                    .getColumnBuilder(1)
                                    .writeBinary(new Binary(String.valueOf(MNodeType.UNIMPLEMENT.getNodeType())));
                            tsBlockBuilder.declarePosition();
                        });
            }
        } catch (MetadataException e) {
            throw new RuntimeException(e.getMessage(), e);
        }
        return tsBlockBuilder.build();
    }

    @Override
    public boolean hasNext() {
        return !isFinished;
    }

    @Override
    public boolean isFinished() {
        return isFinished;
    }

    @Override
    public PlanNodeId getSourceId() {
        return sourceId;
    }

    @Override
    public long calculateMaxPeekMemory() {
        return DEFAULT_MAX_TSBLOCK_SIZE_IN_BYTES;
    }

    @Override
    public long calculateMaxReturnSize() {
        return DEFAULT_MAX_TSBLOCK_SIZE_IN_BYTES;
    }

    @Override
    public long calculateRetainedSizeAfterCallingNext() {
        return 0L;
    }
}
